For a storage apparatus that stores therein data, there is known a method for reducing electric power consumption of the storage apparatus by stopping, for example, turning off at least one of a plurality of storage devices included in the storage apparatus. Examples of the storage devices include a semiconductor drive device such as a solid state drive (SSD) and a magnetic disk device such as a hard disk drive (HDD).
Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication No. 2006-31668 and Japanese Laid-open Patent Publication No. 2002-304353.
When an access is made to a storage resource, for example, a storage device in a stopped state in a storage apparatus including stopped storage devices, the storage apparatus reactivates the storage device in the stopped state and then performs processing in accordance with an access request, which causes a response delay.